/*
* JEF - Copyright 2009-2010 Jiyi (mr.jiyi@gmail.com)
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package jef.tools;
import java.io.CharArrayWriter;
import java.io.IOException;
import java.io.Reader;
public class ByteUtils {
/**
* 将long转换为byte[8](高位在前)
* @param l
* @return
*/
public static byte[] toBytes(long l){
byte[] b=new byte[8];
putLong(b, l, 0);
return b;
}
/**
* 将int转换为byte[4](高位在前)
* @param i
* @return
*/
public static byte[] toBytes(int i){
byte[] b=new byte[4];
putInt(b, i, 0);
return b;
}
/**
* 将short转换为byte[2]. 高位在前，低位在后
* @param i
* @return
*/
public static byte[] toBytes(short i){
byte[] b=new byte[2];
putShort(b, i, 0);
return b;
}
/**
* 将short放入byte数组，高位在前，低位在后
* @param b byte数组
* @param s 要放入的值
* @param offset 所在序号
*/
public static void putShort(byte b[], short s, int offset) {
int len=b.length;
if(offset<len)b[offset] = (byte) (s >> 8);
if(offset+1<len)b[offset + 1] = (byte) (s >> 0);
}
/**
* 将short放入byte数组，低位在前，高位在后
* @param b byte数组
* @param s 要放入的值
* @param offset 所在序号
*/
public static void putReverseBytesShort(byte b[], short s, int offset) {
int len=b.length;
if(offset<len)b[offset] = (byte) (s >> 0);
if(offset<len)b[offset + 1] = (byte) (s >> 8);
}
/**
* 从字节组中获得long（正常顺序：高位在前，低位在后）
* @param b
* @param offset
* @return
*/
public static short getShort(byte[] b, int offset) {
return (short) (((b[offset] << 8) | b[offset + 1] & 0xff));
}
/**
* 从字节数组中获得short,(高位在后，低位在前)
* @param b
* @param offset
* @return
*/
public static short getReverseBytesShort(byte[] b, int offset) {
return (short) (((b[offset + 1] << 8) | b[offset] & 0xff));
}
// ///////////////////////////////////////////////////////
/**
* 将short放入byte数组，高位在前，低位在后
* @param b byte数组
* @param s 要放入的值
* @param offset 所在序号
*/
public static void putInt(byte[] bb, int x, int offset) {
bb[offset + 0] = (byte) (x >> 24);
bb[offset + 1] = (byte) (x >> 16);
bb[offset + 2] = (byte) (x >> 8);
bb[offset + 3] = (byte) (x >> 0);
}
/**
* 将int放入byte数组，低位在前，高位在后
* @param b byte数组
* @param s 要放入的值
* @param offset 所在序号
*/
public static void putReverseBytesInt(byte[] bb, int x, int offset) {
bb[offset + 3] = (byte) (x >> 24);
bb[offset + 2] = (byte) (x >> 16);
bb[offset + 1] = (byte) (x >> 8);
bb[offset + 0] = (byte) (x >> 0);
}
/**
* 从字节流中读取一个int(占4个 byte,高位在前低位在后)
* @param bb
* @param offset
* @return
*/
public static int getInt(byte[] bb, int offset) {
return (int) ((((bb[offset + 0] & 0xff) << 24) | ((bb[offset + 1] & 0xff) << 16) | ((bb[offset + 2] & 0xff) << 8) | ((bb[offset + 3] & 0xff))));
}
/**
* 从字节流中读取一个int(占4个 byte,低位在前，高位在后)
* @param bb
* @param offset
* @return
*/
public static int getReverseBytesInt(byte[] bb, int offset) {
return (int) ((((bb[offset + 3] & 0xff) << 24) | ((bb[offset + 2] & 0xff) << 16) | ((bb[offset + 1] & 0xff) << 8) | ((bb[offset + 0] & 0xff))));
}
// /////////////////////////////////////////////////////////
/**
* 将long放入byte数组，高位在前，低位在后
* @param b byte数组
* @param s 要放入的值
* @param offset 所在序号
*/
public static void putLong(byte[] bb, long x, int offset) {
bb[offset + 0] = (byte) (x >> 56);
bb[offset + 1] = (byte) (x >> 48);
bb[offset + 2] = (byte) (x >> 40);
bb[offset + 3] = (byte) (x >> 32);
bb[offset + 4] = (byte) (x >> 24);
bb[offset + 5] = (byte) (x >> 16);
bb[offset + 6] = (byte) (x >> 8);
bb[offset + 7] = (byte) (x >> 0);
}
/**
* 将long放入byte数组，低位在前，高位在后
* @param b byte数组
* @param s 要放入的值
* @param offset 所在序号
*/
public static void putReverseBytesLong(byte[] bb, long x, int offset) {
bb[offset + 7] = (byte) (x >> 56);
bb[offset + 6] = (byte) (x >> 48);
bb[offset + 5] = (byte) (x >> 40);
bb[offset + 4] = (byte) (x >> 32);
bb[offset + 3] = (byte) (x >> 24);
bb[offset + 2] = (byte) (x >> 16);
bb[offset + 1] = (byte) (x >> 8);
bb[offset + 0] = (byte) (x >> 0);
}
/**
*
* @param bb
* @param offset
* @return
*/
public static long getLong(byte[] bb, int offset) {
return ((((long) bb[offset + 0] & 0xff) << 56) | (((long) bb[offset + 1] & 0xff) << 48) | (((long) bb[offset + 2] & 0xff) << 40) | (((long) bb[offset + 3] & 0xff) << 32) | (((long) bb[offset + 4] & 0xff) << 24) | (((long) bb[offset + 5] & 0xff) << 16)
| (((long) bb[offset + 6] & 0xff) << 8) | (((long) bb[offset + 7] & 0xff) << 0));
}
/**
*
* @param bb
* @param offset
* @return
*/
public static long getReverseBytesLong(byte[] bb, int offset) {
return ((((long) bb[offset + 7] & 0xff) << 56) | (((long) bb[offset + 6] & 0xff) << 48) | (((long) bb[offset + 5] & 0xff) << 40) | (((long) bb[offset + 4] & 0xff) << 32) | (((long) bb[offset + 3] & 0xff) << 24) | (((long) bb[offset + 2] & 0xff) << 16)
| (((long) bb[offset + 1] & 0xff) << 8) | (((long) bb[offset + 0] & 0xff) << 0));
}
/**
* 将byte转换为int
* @param b
* @return
*/
public static int byteToInt(byte b){
return b>= 0 ? b : 256 + b;
}
/**
* 将long转换为指定字节数的数组
*/
public static byte[] longToBytes(long x,int size){
byte[] bb=new byte[size];
for(int n=0;n<8;n++){
if(size==n)break;
bb[n]=(byte)(x>>(8*n));
}
return bb;
}
/**
* 从字节码转换成Long
* @Title: bytesToLong
*/
public static long bytesToLong(byte[] bs) {
long rst = 0;
for (int n = 0; n < bs.length; n++) {
long s = (long) bs[n] >= 0 ? bs[n] : 256 + bs[n];
rst |= s << (n * 8);
}
return rst;
}
/**
* 判断buf中的开头字节是否匹配key中的所有字节
* @param buf
* @param key
* @return
*/
public static boolean matchStart(byte[] buf, byte[] key) {
if(key.length>buf.length){
return false;
}
for(int i=0;i<key.length;i++){
if(buf[i]!=key[i]){
return false;
}
}
return true;
}
/**
* 将输入流中所有非[0-9a-fA-F]以外的字符全部丢弃，然后作为16进制文本，转换为原始的字节数组
* @param input
* @return
* @throws IOException
*/
public static byte[] hexReader2byte(Reader input) throws IOException {
CharArrayWriter cw=new CharArrayWriter(512);
int c;
while((c=input.read())>-1){
if(c<48 || (c>57 && c<65) || (c>70 && c<97) || c>102){
continue;
}
cw.append((char)c);
}
return hex2byte(cw.toCharArray(), false);
}
/**
* 将二进制文本列表转换为字节数组
* @param hexString
* @param hasSpace
* @return
* @throws IOException
*/
public static byte[] hex2byte(char[] hexString, boolean hasSpace) throws IOException {
int len = hexString.length;
byte[] result = new byte[hasSpace ? (len + 1) / 3 : len / 2];
int count = 0;
for (int i = 0; i < len; i++) {
char c1 = hexString[i];
char c2 = hexString[++i];
int i1 = hexChar2dec(c1);
int i2 = hexChar2dec(c2);
result[count++] = (byte) ((i1 << 4) + i2);
if (hasSpace)
++i;
}
return result;
}
/**
* byte2hex的逆运算（有实际用处吗？） 实际使用可以用Byte Byte.parseByte("dd", 16);
*
* @param hexString
* @return
* @throws IOException
*/
public static byte[] hex2byte(CharSequence hexString, boolean hasSpace) throws IOException {
int len = hexString.length();
byte[] result = new byte[hasSpace ? (len + 1) / 3 : len / 2];
int count = 0;
for (int i = 0; i < len; i++) {
char c1 = hexString.charAt(i);
char c2 = hexString.charAt(++i);
int i1 = hexChar2dec(c1);
int i2 = hexChar2dec(c2);
result[count++] = (byte) ((i1 << 4) + i2);
if (hasSpace)
++i;
}
return result;
}
/*
* 将输入的十六进制字符转换为十进制数字
*/
private static int hexChar2dec(char hex) {
if (hex > 47 && hex < 58) {
hex -= 48;
} else if (hex > 64 && hex < 71) {
hex -= 55;
} else if (hex > 96 && hex < 103) {
hex -= 87;
} else {
throw new RuntimeException(hex + "is not a valid hex char.");
}
return hex;
}
}